1. Field of the Invention
The present invention relates to a so-called oil cylindrical rotational damper in which a viscous fluid such as a silicone oil damps its axial rotation, and an assist grip into which this oil cylindrical rotational damper is built-in.
2. Description of the Related Art
A conventional oil cylindrical rotational damper includes a housing which has an inner cylinder and an outer cylinder. The damper also includes an oil reservoir formed between the inner cylinder and the outer cylinder. The oil reservoir is filled with a viscous fluid. A rotor is provided which is immersed in the viscous fluid. The damper further includes two sealing members for preventing leakage of the viscous fluid, and a cap for pressing and holding the sealing members, wherein a shaft member is made to pass through the inner cylinder and the rotor.
In this conventional damper, the cap and the rotor are formed integrally with each other, and the cap engages with the housing in order to press and hold the sealing members.
However, since the rotor or the cap to which a load is applied is structured to press the sealing members and irregularity in the pressing force exerts an adverse effect on the sealing performance of the sealing members, stable, excellent sealing performance over a long period of time cannot be expected. Further, there is a possibility that adverse effects on the damping of the rotor (torque performance) may arise.
An advantage of the present invention is to provide a damper which can overcome the aforementioned conventional drawbacks, which is structured simply, which is made compact and light, and which is manufactured inexpensively, and an assist grip into which the damper is built.
In order to solve such problems as described above, in accordance with the present invention, there is provided a rotational damper including a housing having an inner cylinder and an outer cylinder disposed concentrically with each other and an annular space formed between the inner cylinder and the outer cylinder containing a viscous fluid. A cylindrical rotor is accommodated in the housing and receives a damping action from the viscous fluid. A ring-shaped sealing member is provided for preventing viscous fluid leakage. The damper also includes an annular cap provided independently of the rotor and mounted to the housing, and which retains the rotor and the sealing member in the housing.
There is provided another rotational damper. The damper ficludes a housing having an annular space containing a viscous fluid. A cylindrical rotor is accommodated in the housing and receives a damping action from the viscous fluid. An annular cap is provided independently of the rotor and engaged with the housing, which retains the rotor in the housing. A ring-shaped first sealing member is disposed between the rotor and the cap and a
There is provided an assist grip including an arm supported so as to be rotatable between a first angular position during use and a second angular position during non-use, with the arm biased to return from the first angular position to the second angular position. The assist grip also includes a damper for damping arm rotation with the damper including a housing containing a viscous fluid; a cylindrical rotor accommodated in the housing for receiving a damping action from the viscous fluid, an annular cap having a central aperture and provided independently of the rotor, and which retains the rotor in the housing, a ring-shaped first sealing member disposed between the rotor and the cap, and a ring-shaped second sealing member disposed between the rotor and the housing. The cylindrical rotor includes a cylindrical head having an end side with a first hollow cylindrical portion threat. The first hollow cylindrical portion is passed through the central opening of the annular cap, with the first sealing member disposed between the first hollow cylindrical portion and the central aperture of the annular cap.
There is provided another assist grip. The assist grip includes an arm supported so as to be rotatable between a first angular position during use and a second angular position during non-use and biased to remain in the second angular position. The assist grip also includes a damper for damping rotation of the assist grip, the damper including a housing containing a viscous fluid; the housing having an inner cylinder, a cylindrical rotor accommodated in the housing and for receiving a damping action from the viscous fluid; an annular cap having a central aperture and provided independently of the rotor and which retains the rotor in the housing, shaped first sealing member disposed between the rotor and the cap, and a ring-shaped second sealing member disposed between the rotor and the housing. The cylindrical rotor is provided with a cylindrical head, having opposite ends and having a first hollow cylindrical portion at one of the end sides, the first hollow cylindrical portion being passed through the central aperture of the annular cap. The cylindrical rotor includes a second hollow cylindrical portion at the other end side of the cylindrical head. A portion of the inner cylinder of the housing enters into the second hollow cylindrical portion. The cylindrical rotor has a damping cylinder provided independently of the cylindrical head and the second sealing member is disposed between the second hollow cylindrical portion and the damping cylinder.